A threat was written on a wall.

SPRING VALLEY - Students returned to Spring Valley High School after being evacuated for nearly one hour on Friday due a bomb threat found written on a classroom blackboard, authorities said.

A copycat bomb scare was later called into Ramapo High School, leading to the arrest of a 17-year-old Spring Valley resident.

The Spring Valley High School message was, "There's a bomb. Evacuate the school," said Tom Carton, coordinator of safety and security for the East Ramapo Central School District.

Carton said he was called about the threat at 7:29 a.m. and he called the Spring Valley police after arriving at the school within minutes.

He said the students were evacuated at 7:55 a.m. after seven buses were brought to the school so students could keep warm while outside. The Rockland Sheriff's Office bomb squad also responded to Spring Valley High School at 361 E. Route 59.